Bug 523942

Summary:	media-video/ffmpeg - remove CFLAGS override for -march=native
Product:	Gentoo Linux	Reporter:	Sebastian <sebastian_ml>
Component:	Current packages	Assignee:	Gentoo Media-video project <media-video>
Status:	RESOLVED WONTFIX
Severity:	normal	Keywords:	PATCH
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Attachments:	ffmpeg-no-cflags-override.patch

Description Sebastian 2014-09-28 13:15:28 UTC

Hello,

Please consider removing the lines from the ebuilds that replace "native" with "host". They stem from bugs 172723 and 273421, from the year 2007 and 2009 respectively.

Now - many years later - ffmpeg compiles fine with -march=native. I don't see why these lines would still be warranted.

I had requested the same for libav earlier, and it was committed, see bug 458768.

Reproducible: Always

Comment 1 Sebastian 2014-09-28 13:16:30 UTC

Created attachment 385672 [details, diff]
ffmpeg-no-cflags-override.patch

Patch to remove the override from the current ebuilds.

Comment 2 Alexis Ballier gentoo-dev

2014-10-05 06:24:23 UTC

this patch is just as wrong for libav as it is for ffmpeg

ffmpeg uses the cpu fed at configure to determine which hand written asm is better to use: have a look at configure. you should really diff the output of configure with and without this on x86; for example, here is disables 'fast_cmov'.

plus, it helps for cross-compile optimizations.

Comment 3 Sebastian 2014-10-05 10:42:11 UTC

Hello Alexis,

Thanks for pointing this out. I reopened the old bug to get the change reverted.

Kind regards,
Sebastian